FALLUJAH, IRAQ
— The four insurgents were heavily outnumbered and outgunned by US marines in Fallujah.

But armed with just assault rifles and grenades, the quartet locked an entire company in intense battle for hours, inflicting casualties in hand-to-hand combat and delivering a tough lesson for US forces as they deepen their hunt for an ephemeral and patient enemy that embraces martyrdom.

The climax of the firefight late Monday night could not have been more chaotic or more illuminating of the horrors of urban conflict.

When the team from Alpha Company finally entered the last redoubt of the insurgents - a burning house that had already been hammered by rockets, explosive charges, and tank rounds - they had every reason to believe any remaining gunmen were dead.

Instead, point man Lance Corp. Richard Caseras entered with his team and ran into the spray of an insurgent's AK-47 assault rifle. A second fighter then emerged, a pineapple grenade in each hand, with pins already pulled.

Eyeball to eyeball with their opponents, the marines shot them both dead; the grenades fell to the ground and exploded, blasting the Americans with shrapnel.

The result was a panicked war scene that could have been drawn from the film "Apocalypse Now." In the eerie light of the roaring flames, the wounded men were dragged back out to the street while marines targeted the house with steady gunfire.

US commanders say that such costly battles are taking place across Fallujah, where US Marine and Army units launched an assault more than two weeks ago in a bid to cut off the lethal insurgency that has spread across Iraq.

But the battle Monday, fought amid the maze of houses and alleyways in this ghost city that once held a population of 300,000, shows the difficult and dangerous task of uprooting insurgents who have hunkered down. Protecting civilians may also prove a daunting task as marines try to locate fighters who filter quietly back in as residents return.

"You are seeing individuals willing to die, and take as many Americans and Iraqis with them," says Marine Maj. Gen. Richard F. Natonski, 1st Marine Division commander in an interview. "We overwhelm them, but despite that, they put up a very stiff and determined resistance. This [assault] had to be done, because Fallujah was a sanctuary for insurgents, and now it isn't."

As the shooting lit the battlespace with muzzle flashes and noise, a lone US Navy medical corpsman jumped out to gather the wounded. This correspondent moved to help, joining in to pull the three injured men into the vehicle by their flak jackets.

"I'm so sorry! I should have used the frag[mentation] grenade, and not my M-16 [rifle]," Lance Corporal Caseras yelled to his fallen comrades as the vehicle raced toward a combat hospital at Camp Fallujah. Lance Corp. Nathan Douglass was peppered with shrapnel. Also prone in the back of the armored vehicle, on crates full of ammunition and explosives, lay Corp. Catcher Cuts the Rope (his native American name), with a tourniquet above his knee; grenade shards hit his shoulder and hands.

"Don't worry," Corporal Douglass, from Hillsboro, Ore., said consolingly. "We shot so much into that house. There shouldn't have been anybody left."

The final blow came with heavy fire from a Spectre AC-130 gunship, which destroyed four houses used by the insurgents with 40 Howitzer shells.

The toll from a brutal night: One dead marine and nine wounded, including this correspondent, who was struck in the arm by a small piece of shrapnel.

The firefight brings the casualty rate in the Light Armored Reconnaissance (LAR) company to 1 man in 5; far less than the 60 percent reached during the battle for Vietnam's Hue City in 1968, the last urban assault before Fallujah waged by US Marines - but far higher than most modern combat operations.

The morning after the battle, as marines returned to the site to further clear the houses, two very young boys emerged from a house across the street, waving in a friendly way at the marines. They were followed by a woman in a black shroud and an older man. A cardboard sign on the wall, invisible during the firefight the night before, read: "There is family."

After granting civilians four hours each day to visit local food-distribution centers, commanders Wednesday extended the curfew to 24 hours a day. A jobs program was put on hold; it is not clear when civilians will be allowed to return.

And insurgents are still being found. On Tuesday, an LAR patrol uncovered five foreign men, suspected of being insurgents, hiding in a house. They had wounds, $1,100 in crisp hundred-dollar bills, and false identification papers.

"It's a man-on-man fight, a classic infantry battle," says marine Col. Craig Tucker, commander of the Regimental Combat Team-7, one of two regiments fighting in Fallujah.

"If you've got a guy sitting in a house with two grenades, who knows he is going to die, we're going to root these guys out, house by house," says Colonel Tucker. "[But] you can't go into every house and knock it down, It's the difference between an organization that follows the rules of war, and one that does not. The challenge for us, is not becoming them."

Such guerrilla tactics, which in the past week have included using a white surrender flag as a cover for attack, or playing dead on the street before jumping up to fire - have kept these marines on edge.

But even as US units apply overwhelming force, they are at risk from the asymmetrical threat posed by rebels - and the presence of civilians.

"I'm telling you marines, you have the authority to use lethal force," Captain Gil Juarez, the LAR commander, told his platoon chiefs when giving the order for Monday's operation. "But be advised: If you make a mistake and frag innocent civilians, there is going to be a [military lawyer] on the scene, and an investigation."

"We'll win the battle, no problem," Captain Juarez continued. "But this is still a war about human relations. This is political war. Everything we do must help toward winning that war."

A clear example of the tricky balance is Monday's battle, which started out as a typical clearing operation, in which LAR vehicles and on-foot scout teams pushed east to west between two clocks, clearing house after house.

Red Platoon began in typical fashion, with a reading the 91st Psalm from the Bible.

"Thou shalt not be afraid of the terror by night; nor for the arrow that flieth by day; nor for the pestilence that walketh in darkness," read Corporal Dustin Barker of Midland, Texas. Citations from the Bible mark his helmet strap.

The marines used explosives, axes, and even their boots to break down doors and storm houses.

They searched rooms and destroyed food stores when they found them to deprive insurgents moving from house to house of support.

"The problem with this, is we are opening [by breaking locks] the whole town up for terrorists to move in," said an intelligence officer with the unit.

In one house, Red platoon found two men sitting around a heater, drinking tea. The kitchen was immaculate - except for a single bowl of beans and another of rice - and did not look as if it had been lived in for weeks. The phone's answering machine had received 61 unanswered calls, up until Nov. 5.

The men knew their own names, but little else. They couldn't identify the couple in the marriage photo above the master bed, and said they had cut it out of a magazine. They were detained.

The first contact for Alpha Company came shortly after a block away.

One marine was shot when he entered a house, and later died on his way to the combat hospital. Corp. Luiz Munoz was also shot in the leg.

The shooting launched the battle. Also wounded was Corp. Peter Mason, a veteran, like this Alpha platoon, of a battle on Nov. 13 that left 15 guerrillas dead.

On that day, he was shot four times in his armor plates and once in the helmet. Eight more bullets put holes in his trousers, but missed his legs.

Even as Corporal Mason was treated for shrapnel wounds Monday, in the gathering twilight, marines shot a second insurgent on the roof.

Then they climbed to the next building to fire three rockets. Two more hours of nighttime combat passed when the fire team entered yet another house, and ran into the rifle fire and grenade carrier.

"I don't know how we can prevent that [in the future]. We did everything right," says Lieut. Matt Bronson, the platoon commander of the teams first into the house, from Barre, Mass. "They are just hoping we don't come into their house; they are waiting for civilians to come back."

"Once those Abrams [tanks] started shooting, I thought: 'If [the insurgents] are still alive, they are going to be very [angry]," Lance Corporal Donald Blais told his wounded platoon-mates, during a visit that night at the combat hospital.

"The living room was on fire when we went in. It still hasn't hit me yet," says Corporal Blais, his face was blackened from fire smoke and accumulated dirt of two weeks of war. He says he shot 15 magazines of ammunition that night - some 400 bullets.

"Every time I close my eyes, I see the house burn," says Blais, of Hartford, Conn. "I don't think I can sleep."

"I see the glowing of the fire," adds Douglass, a month shy of his 20th birthday, as he lay in his hospital cot.